No usable peer 'nonexistent-peer' exists in 'netdev' datapath.

[wuqiang0720]

I met a issue find the below error,but it seems not impact traffic,and I checked the related patch is successful added.is it a bug.in ovs 2.12?
No usable peer 'nonexistent-peer' exists in 'netdev' datapath.

[chaudron]

This error message is reported when the peer of a patch port can not be found, so you might want to verify your patch port configuration. In addition, OVS 2.12 is no longer supported, so you might want to try a more recent version of OVS.

[igsilya]

@wuqiang0720 This log says that you added a patch port with the peer name "nonexistent-peer" and that there is no such port. Looking at the name, I'd guess it's expected that this port doesn't exist. Not sure what the intention was here as patch ports without a peer make no sense, but it doesn't look like anything is wrong in OVS here.

[wuqiang0720]

the two patch ports are added normally, but this error does not disappear, there is only one node have this issue.

[wuqiang0720]

        Controller "txxx"
            is_connected: true
        fail_mode: secure
        datapath_type: netdev
        Port phy-br_prv
            Interface phy-br_prv
                type: patch
                options: {peer=int-br_prv}
                error: "No usable peer 'nonexistent-peer' exists in 'netdev' datapath."
        Port bond_prv
            Interface "data0"
                type: dpdk
                options: {xxx"}
            Interface "data1"
                type: dpdk
                options: {xxx}
        Port br_prv
            Interface br_prv
                type: internal
    Bridge br-int
        Controller "xxx"
            is_connected: true
        fail_mode: secure
        datapath_type: netdev
        Port int-br_prv
            Interface int-br_prv
                type: patch
                options: {peer=phy-br_prv}
                error: "No usable peer 'phy-br_prv' exists in 'netdev' datapath."
        Port br-int
            Interface br-int
                type: internal

[igsilya]

OK. It looks like the patch ports were first created with "peer=nonexistent-peer", but then updated with the actual peer name, but the error wasn't cleared from the database for some reason. This indeed looks like a bug in OVS. But the issue should not impact the actual traffic. I'll second Eelco here and suggest to try a newer version. Current LTS release is 3.3. OVS 2.12 is not supported for about 4 years now.

[wuqiang0720]

@igsilya do you have the official document related to this bug. I think this is a rare issue, but two times we encounter.

[wuqiang0720]

this issue happened during neutron-openvswitch-agent restarting,

delete those patch port and repeating restart neutron-openvswitch-agent 20 times or more，
this issue will happen
I think this is a bug，the interval of two patch port creation is too short.need to update neutron related code.

[igsilya]

@wuqiang0720 could you try the following change in your setup?

diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 456b784c0..e879b6df6 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -2641,6 +2641,9 @@ iface_refresh_ofproto_status(struct iface *iface)
         ovsrec_interface_set_error(iface->cfg,
                                    errp ? errp : ovs_strerror(error));
         free(errp);
+    } else if (iface->cfg->error) {
+        ovsrec_interface_verify_error(iface->cfg);
+        ovsrec_interface_set_error(iface->cfg, NULL);
     }
 
     current = ofproto_port_is_lacp_current(iface->port->bridge->ofproto,

[wuqiang0720]

@igsilya I don't know where is the /vswitchd/bridge.c, I installed ovs with rpm..

[igsilya]

@wuqiang0720 it's part of the source code, you'll need to modify the source rpm and rebuild the package.

[wuqiang0720]

I get it, is it a bug in some version.

[wuqiang0720]

• } else if (iface->cfg->error) {

•    ovsrec_interface_verify_error(iface->cfg);
  

•    ovsrec_interface_set_error(iface->cfg, NULL);
  

I update this code,then this issue will not happen,but I'd like to know does any version will update this code？

[igsilya]

@wuqiang0720 if you can confirm that this change fixes your issue, then we can get it applied to main and then backported down to OVS 3.3 LTS, which is the oldest currently supported version.

[wuqiang0720]

thanks @igsilya , is there any official document to describe this issue?

[igsilya]

@wuqiang0720 we don't have any such documents. This issue tracker and the mailing list are as official as it gets.